Djokovic: Nadal can be the greatest

Novak Djokovic has backed Rafael Nadal to become the greatest player of all time after failing to prevent the Spaniard from completing a sweep of the four grand slam titles in New York.

Nadal claimed the US Open with a 6-4 5-7 6-4 6-2 success at Flushing Meadows to add to the crowns won previously at the Australian Open, French Open and Wimbledon. The world number one becomes the seventh man to achieve the feat - and the third youngest behind Rod Laver and Don Budge.

"He has the capabilities already to become the best player ever," said Djokovic.

"I think he's playing the best tennis I have ever seen him play on hard courts. He has improved his serve drastically. The speed, the accuracy, and of course his baseline is as good as ever, so he's a very complete player."

Having beaten Roger Federer - a winner of 16 grand slam events and widely regarded as the benchmark when discussing the greatest of all time - in the semi-finals and then faced Nadal in the title showdown, Djokovic is well-placed to compare the two.

He added: "At this point there is five, six years' difference between them, and basically Federer has had more years on the tour, he has had more success; he has more trophies.

"He's definitely somebody who made history in this sport. And he's still playing as one of the best players in the world.

"On the other hand, you have Nadal who is just proving each day, each year that he's getting better. That's what's so frustrating. He's getting better each time you play him.

"He's so mentally strong and dedicated to this sport. He has all the capabilities, everything he needs, in order to be the biggest ever, in my opinion.

"He has lots to come if he physically holds in the next five, six, seven years."